Electron discharge device employing a cavity resonator



s. NERGAARD 2,431,273 ELECTRON DISCHARGE DVICE EMPLOYINGA GAVITYRESONATOR Nov. 18, 19477 Filed Aprillv, 1944 5 Sheets-Sheet 1 fa l f l 9Z w NJ. HHH a .3 n Z H Q Z f\/ I 3)( J f f d? 5 /J 0 mb Z ,2 A 1 ,n 5 loO l A 5 0d I 5f! Il: @n MAIl..

Nov. 18, 1947. s, NERGAARD ELECTRON DISCHARGE DEVICE EMPLOYING A CAVITYRESONATOR 3 sheets-sheet? Filed April 1'7, 1944 Snventor Gttorneg Nov.18,y 1947.V 1 s, NERGAARD 2,431,273

ELECTRON DISCHARGE DEVICE EMPLOYING A CAVITY RESONATOR` Filed April 17,1944 3 Sheets-Sheet 5 :inventor (Ittorneg Patented Nov. 18, 1947ELECTRON DISCHARGE DEVICE EMPLOY- ING A CAVITY RESONATR Leon Nergaard,Princeton, N. J., assigner to Radio Corporation of America, acorporation of Delaware Application April 17, 1944, Serial No. 531,312'I19 claims. 1

My invention relates to apparatus useful at ultra-high frequencies andmore particularly to electron discharge devices and associated circuitsof the cavity resonator type.

An object of my invention is to provide an electron discharge device andassociated circuit particularly suitable for high frequency operationand capable of delivering large amounts of power.

Another object of my invention is to provide an electron dischargedevice which can deliver large amounts of power at high frequencies, butwhich -1s nevertheless small and compact, has few parts, and lendsitself readily to manufacture.

A more speciiic object of my invention is to provide an electrondischarge device in which the electrodes although closely spaced arefirmly and rigidly supported with respect to each other.

A further object of my invention is to provide an electron dischargedevice having electrode leads and supports which will merge into highfrequency circuits of the cavity resonator type so that the internalreactances may be coupled smoothly to the external reactances whichcomplete the circuit and thus reduce radio frequency losses and spuriousmodes of oscillation to a minlmum.

Another vspecific object of my invention is to provide a cathode whichwill promote heater power economy.

A further object of my invention is to provide a cavity resonatorcircuit in which the circuit has large ldimensions while permittingoperation at very high frequencies.

Another vobject of my invention is to provide an electron dischargedevice and associated circuits comprising cavity resonators whichprovide a novel method of introducing biasing voltages on the electrodesenclosed within the cavity resonators.

A further object of my invention is to provide improved means forconnecting the terminals of an electron discharge device to a cavityresonator circuit.

Another object of my invention is to provide push-pull circuits for anelectron discharge device made according to my invention and using anovel type of coaxial line resonator.

A still further object of my invention is to provide an electrondischarge device of the type described above utilizing a novel cavityresonator circuit associated therewith and novel means for cooling thedevice during operation.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims, but the inven-vtion itself will best be understood by reference to the followingdescription taken in connection with the accompanying drawing in whichFigure 1 is a longitudinal section of an electron discharge device andassociated circuit made according to my invention; Figure 2 iS alongitudinal section of an electron discharge device made according tomy invention and of the type utilized in Figure l; Figure 3 is alongitudinal section of a modification of the electron discharge deviceand associated circuit shown in Figure 1, and Figure 4 is a longitudinalsection of the electrondischarge device shown in Figure 3. f

In accordance with my invention I provide an electron discharge devicehaving an indirectly heated cathode I0 of cup-shape surrounded by acup-shaped grid II, both nested within anode I2 provided withlongitudinally extending heat radiating ns I3. The anode provides partof the envelope and is provided with a collar I4 of U- shaped transversesection. aThe outer rim of the collar ll is sealed to the insulatingcollar I5. The header for the tube envelope includes a disc member i9welded at I1 to a collar I 6 sealed to the other end of insulatingcollar I5. The disc or header is is provided with collar I8 sealed bymeans of a transverse flat press 20 through which the leads i3 extend.These leads support the conducting collar 2l on which the cathode ismounted. The grid is supported by means of cone-shaped collar 22 mountedon the disc I9. This device will be described in more detail below inconnection with Figure 2.

An input circuit of the coaxial line type providing a cavity resonatoris coupled to the device described and comprises an inner tubular member25 capacity coupled to the cathode leads. A collar 28 provides thecathode lead socket and is capacity coupled toy the tubular member 25through the insulating collar 2S, preferably of mica. The outer tubularmember 26 is connected to the inner tubular member by closure member 2l.The outer tubular member is provided with a plurality of spring fingers32 engaging the outer periphery of the header member I9, upon which thegrid is supported and toy which it is electrically connected. A snortingmember 3| tunes the circuit. rihus the cavity resonator is coupledbetween the grid and cathode of the electron discharge device.

The output circuit is a novel push-pull cavity resonator type andcomprises an inner tubular member 35 which receives within one end theradiating iins i3 and the anode I2 of the electrQIl discharge device andthe outer tubular member 38 surrounding the inner tubular member. Thiscircuit can operate in a half wave mode or a multiple thereof dependingupon the adjust- `ment of the cathode circuit.

At the other end of the output cavity resonator is a second electrondischarge device of the type rst described. A coaxial input circuit 25identical with that connected to the electron discharge device rstdescribed is coupled to the cathode and grid of this second electrondischarge device and the member 35 receives within it the anode I2 andradiating ns I3.

The outer tubular member 38 of the cavity resonator has an aperture 31through which tubular member 36 extends, this member being connectedelectrically to the inner tubular member 35 of the cavity resonator.This tubular member 36 serves as a lead for the anode voltage and alsoas a duct for directing cooling air inte the inner member 35 and outinto the outer member past the longitudinally extending cooling iins I3and I 3 over the insulating collar members I and I5', and back outthrough the aperture 31. The output may be taken by means of a coaxialliner comprising inner conductor 35 and outer conductor 38'. Feedbackmay be of any type but is shown as a coaxial coupling line coupledbetween the input and output circuits and including an inner conductor25 and an outer conductor 26".

- The electron discharge device uti1ized :in my one end of which isconnected to the cathode and theother end of Which is connected by meansof lead IIJ to a lead wire 48' `sealed through the press 20. Thelead-in'conductors 48 mounted in a circle are enclosed within andconnected to a supporting cathode collar 2l, the cathode proper beingsupported' by means of ribbon-like conducting members 41 to reduce heatconduction between the cathode and collar 2I. The grid II is providedwith a top cap II' having a plurality of apertures I l'f for reducingheat iiow from the center of the cap to the grid wires. The top cap has,a cathode-grid aligning hole in the center through which the conductor49 from the cathode i extends and is supported from the top cap by meansof the insulating tubular member 53, The grid I I is iirmly and rigidlysupported by means of the cone-shaped member 22 sealed to the headermember I3, which may be a fernico ring.

V'Ihe cathode may b e of silicon nickel ribbon coated on the surfacewith the usual carbonates.

'Ihe lower end of the cathode thimble is closed by heat shield 46.tungsten wire and cylinder 2| may be nickel and The heater ID' may beofthev supporting tabs 41 may be of copper plated kovar, the tabs servingto heat insulate the cathode Vas well as provide electrical contact.There is no contact between the sleeve 2I and the heater lead 48' towhich the cathode heater lead I0" is connected.A The getter pellet 5 Imay be connected between the lead 49 and the cathode cylinder ZI toprovide a flashing circuit.

As pointed out above, the grid and cathode are enclosed within the anodeI2 provided with -the 7 vertical or longitudinally extending heatradiating ns I3, the anode being a copper thimble to which may be silversoldered the kovar sealing collar or ring I4 of Ytransverse U-section.The envelope is completed by means of the insulating c ollar I5,preferably of glass sealed to the outer 11p of collar I4 and the collarI6A which is provided with a iiange I6 welded at I1 to the disc I9 ofthe header. With the arrangement shown the cathode and grid can be firstmounted on the header member, and the anode assembly sealed thereover todisc I3 by welding. This would avoid the necessity employed in one meth-`od of assembly iirst requiring forming the envelope, cracking thecollar I5 and re-sealing the same after mounting the cathode and gridupon the header. In the arrangement shown there is no danger of crackingof the button stem, due to uneven heating which would occur inre-sealing a cracked envelope collar I5.

The apparatus described can function at very high frequencies, of theorder of 1200 megacycles or higher and deliver large amounts of poweralthough occupying small space, which is of importance in certainapplications, and permits adequate cooling. The tube and circuit mergeinto each other to provide an eicient high frequency apparatus. Thecavity resonator circuits, despite the high frequency at which theapparatus is' designed lto operate, are of reasonable size providingdesirable external reactances which can be tuned. i

In Figure 3 I show a modication of an electron discharge device andassociated circuit made according to my invention. This is a singletubeY circuit utilizing a tube muchlike that shown in Figure 2. Thegrid-anode circuit againrof theY coaxial line type consists of the innertubular member 25", the outer tubular member 23, closure member 2,1coupled between the cathode l0 and grid I I, and the shorting tuningring 3I.

The output circuit now comprises the inner conductor 46 having aslidable collar 41' Yfor determining the length of the inner tubularmeminner and outer tubular'members to direct the iiow of cooling Vairwhich is admitted; at extension 6I into proper channels. The upper endof the member 48" is provided with an aperture surrounded by collar 54through which the inner conductor 55 of the coaxial line,'comprisingconductors 55 and 55', extends, the aperture being sealed by insulatingmember 56, Vand thelowerr end of the coupling member 55 extending withinthe rcollar 41' for coupling the coaxial line to the output circuit. Thecooling medium may be directed through the extension'l along the linesindicated by the arrows for the iiow of the cooling medium, past springs32 into the input circuit, past tuning ring 3l' and rods 3l.V mayoperate in a half wave mode or a multiple thereof.

In Figure 4, showing details, is a modication of the electron dischargedevice shown in' Figure Y 2. Like members designate like parts. Thecathode'heater 51 is slightly different Yand the header membercompris/es ring I5 andis provided'withV oppositely directed flanges 53and 53, the press being supported within and Ysealed to the flange '58,the flange 59 beingV sealed to the insulating collar I5.

While I have indicated `the preferred embodi-fV` Y This Circuit ments ofmy invention `of which I am now aware and have also indicated only onespecific application for which my invention may be employed, it will beapparent that my invention is :by no means limited to the -exact formsillustrated or the use indicated, but that many variations may be madein the particular structure used and the purpose for which it isemployed without departing from the scope of my invention as set forthin the appended claims.

What I claim as new is:

1. An electron discharge device having an anode, a grid and a cathode,resonator means coupled between the cathode and grid, vand a cavityresonator coupled between said grid and anode and having an innerconductor coupled to said anode and comprising an elongated memberengaging and extending from said anode, and a hollow member surroundingthe elongated member but out of electrical contact therewith butenclosing said elongated member, said hollow member having an aperturetherein and means extending through said aperture and connected to saidinner conductor for applying a voltage to said inner conductor.

2. An electron discharge device having an envelope closed at one end byan anode forming part of the envelope for said electron dischargedevice, a grid within said envelope having conducting means extendingradially through said envelope and supporting said grid and a cathodewithin said envelope having conducting means extending through saidenvelope, a cavity resonator coupled between the cathode and gridconducting means and a cavity resonator coupled between said grid andanode and having an inner conductor coupled to said anode and comprisingan elongated member having one end engaging and extending from saidanode and a hollow member surrounding the elongated member but out ofelectrical contact therewith and enclosing said elongated member, saidhollow member having an aperture oppositely disposed to the free end ofthe elongated member and electrically conducting means extending throughsaid aperture and coupled to said elongated member.

3. An electron discharge device having an anode, a grid havingconducting means extending therefrom, and a cathode having conductingmeans extending therefrom, a cavity resonator coupled between thecathode and grid conducting means and an output cavity `yresonatorcoupled between said grid and anode and having an inner conductorcoupled to said anode and compri-sing an elongated member engaging andextending from said anode, a tubular member surrounding the elongatedmember but out of electrical contact therewith and completely enclosingsaid first tubular member, said second tubular member having an aperturetherein, and electrically conducting means extending through saidaperture and coupled to the interior of the output cavity resonator.

4. An electron discharge device having an envelope closed at one end byan anode forming part of the envelope for said electron dischargedevice, a grid within said envelope having conducting 4means extending`radially through said envelope and a cathode within said envelopehaving conducting means extending through said envelope, a cavityresonator coupled between the cathode and grid conducting means and anoutput cavity resonator coupled between said anode and grid andcomprising an inner tubular member engaging and extending from saidanode, an

outer tubular member coupled .to the grid conducting means .andsurrounding the inner tubular member but out .oi electrical contacttherewith and .completely enclosingfsaid inner tubular member, saidouter tubular member having an aperture oppositely disposed to the freeend of the in- -ner tubular member and electrically conducting .meansextending through said aperture and coupled to the free end of saidinner tubular mem'- ber.

. 5. A high frequency apparatus comprising Aa pair of concentric tubularmembers, the inner of said tubular members being open at its ends, saidouter tubular member having apertures in the -ends thereof, a pair ofelectron discharge devices, each electron discharge device having an.anode and extending through an aperture in one end of said outertubular member and `'having its anode extending within an open end ofsaid inner tubular member and engaged thereby, each of said electrondischarge devices including a grid coupled to said outer tubular member,and a cathode, and a cavity resonator coupled between the grid andcathode of each of said electron discharge devices, said outer tubularmember having an aperture therein and a voltage lead extending throughsaid aperture and contacting said inner tubular member.

6. A high frequency apparatus including a pair of oppositely disposedelectron discharge devices each including an anode forming part of theenvelope of the electron discharge device, said anodes being provide-dwith longitudinally extending radiating fins and a cavity resonatorcoupled between said electron discharge devices and including an innertubular member having open ends, the anode of one of said electrondischarge devices being positioned within and engaged by one end or"sai-d inner tubular member and the anode of the other of said electrondischarge devices being within and engaged by the other end of saidinner tubular member, and an outer tubular member surrounding saidelectron discharge devices and said rst tubular member, and a tubularmember extending through but out of contact with said outer tubularmember and opening into the interior of said interior of Sai-d innertubular member for directing a cooling medium within said inner tubularmember and past said radiating ns of said electron discharge devices.

'7. A high frequency apparatus including a pair of oppositely disposedelectron discharge devices each including an anode, a grid and cathode,said anodes forming part of the envelope for said electron dischargedevices and having longitudinally extending radiating iins and a cavityresonator coupled between said electron discharge devices and includingan inner tubular member having open ends, the anode of one of saidelectron discharge devices being positioned Within and engaged by oneend oi' Isaid inner tubular member and the anode of the other of saidelectron discharge devices being Within and engaged by the other end ofsaid inner tubular member, and an outer tubular member surrounding saidelectron discharge devices and said rst tubular member and coupled tothe grids of said electron discharge devices, and a tubular memberextending through but out of contact with said outer tubular member andopening into the interior of said inner tubular member for directing acooling medium within said inner tubular member and past said radiatingfins of said electron discharge devices.

8. A high frequency apparatus comprising a pair of concentric tubularmembers, the inner one of said tubular members being open at its ends,the outer tubular member having apertures in the ends thereof, anelectron discharge device having an anode extending through the aperturein each end of said outer tubular member and having its anode extendingwithin an open end of said inner tubular member andengaged thereby, eachof said electron discharge devices including a grid coupled to ysaidouter tubular member and having a cathode and a resonator means coupledbetween the grid and cathode of each of said electron dischargedevices.r

9. A high frequency apparatus including a pair of oppositely disposedelectron discharge devices each including an anode, a grid and cathode,said anodes forming part of the envelope for said electron dischargedevices and having longitudinally extending radiating fins and a cavityresonator coupled between said electron discharge devices and includingan inner tubular member having open ends, the anode of one of saidelectron discharge devices being positioned within and engaged by oneend of said inner tubular member and the anode of the other of saidelectron Vdischarge devices being within and engaged by the other end ofsaid inner tubular member, and an outer tubular member surrounding saidelectron discharge devices and said rst tubular member and coupled tothegrids of said electron discharge devices, and cavity resonatorscoupled between the grids and cathodes of each of said electrondischarge devices, and a tubular member extending throughV but out ofcontact with said outer tubular memberA and opening into the interior ofsaid inner tubular member for directing a cooling medium within saidinner tubular member and past said radiating iins of said electrondischarge devices.

l0. A high frequency apparatus including a pair of oppositely disposedelectron discharge devices each including an anode forming part of theenvelope for said device, a grid and cathode, a radially extending gridconductor extending through the envelope and a cathode conductorextending through the envelope, said anodes being provided withlongitudinally extending heat radiating fins and a cavity resonatorcoupled between said electron discharge devices and including an innertubular member having open ends, the anode of one of said electrondischarge devices being positioned within and engaged by one end of saidinner tubular member and the vanode of the other of said electrondischarge devices being within and engaged by the other end of saidinner tubular member, and an outer tubular member surrounding saidelectron discharge devices and said first tubular member and coupled tothe grid conductor, and cavity resonators coupled between the grid andcathode conductors of each of said electron discharge devices.

11. A high frequency apparatus including a pair of oppositely disposedelectron discharge devecies each including an anode forming part Vof theenvelope of said electron discharge device, said anode being providedwith longitudinally extending radiating ns, and a cavity resonatorcoupled between said electron discharge devices and including an innertubular member havingY open Yends, the anode of one of said electrondis-r charge devices being positioned within and engridsv withintheenvelopes, and an outer tubular member surrounding said electrondischarge devices and said first tubular member, said outertubular'member being coupled to the grids of said electron dischargedevices and a tubular member extending through but out of contact withsaid outer tubular member and opening into the interior of the innertubular member for directing a cooling medium within said inner tubularmember and past said` radiating fins `of said electron discharge devicesand :resonant means connected between the cathode and grid of each ofsaid electron discharge devices.

12. An electron discharge device having an anode and a cathode, saidanode forming part of the envelope of said electron discharge device, acavity resonator coupled to said electron discharge device and includingan inner tub-ular member having one end engaged with the anode of saidelectron discharge devicev and an outer tubular memberl surrounding saidelectron discharge devicel and said inner tubular member and having anaperture oppositely disposed to the free end of said inner tubularmembenand a coaxial line having inner and outer conductors, the innerconductor extending through said aperture toward the free end of saidinner tubular anode, a gridrand cathode, said anode forming part of theenvelope of said electron discharge device, a cavity resonator coupledto said electron discharge device and including an yinner tubular memberhaving one end engaged with the anode of said electron discharge deviceand an outer tubular member surrounding said electron discharge deviceand said inner tubular member and coupled to said grid and having anaperture oppositely disposed tothe freev end ofV said inner tubularmember, and a coaxial line having inner and outer conductors, the innerconductorextending through said aperture toward the free end of saidinner tubular member. v

`V14. An electron discharge device having an anode and a cathode, said4anode'forming part of the envelope of the electron discharge device andY electronV discharge device and including an inner gaged by one end ofsaid inner tubular member 1V and the anode of the other of said electrondischarge devices being within and engaged by the VVother end of saidinner tubular member, said electron discharge devices having cathodesand hollow member having one end surrounding and Y' engaged with the nson said'anode and an outer Y hollow member surrounding said electrondischarge device and said inner hollow member,

the inner hollow member opening into the interior of said outer hollowmember, saidV outer hollow member having an aperture therein `andtubular means opening into said inner hollow;

member for directing a cooling medium through the Iaperture in saidouter hollow member through said inner hollow member past said fins.

15. An electron 'discharge device having an anode, a grid and cathode,said anode, forming part of the envelope of said electron dischargedevice, a cavity resonator coupled to said electron discharge device andincluding an inner conducting member having one end' engaged withtheanode of said electron 'discharge device and an outer tubular membersurrounding said'ele'ctron discharge device and said inner conductingmember and coupled to said grid and having an aperture oppositelydisposedto the free end of v'the inner conducting member, a coaxial lineopening into said aperture and including outer and inner conductors-'theinner conductor of said coaxial line extending through said aperturetoward the free end of said inner conducting member and resonant meanscoupled to said cathode and said grid, said outer tubular member havinga second aperture, and a lead extending through said second aperture andcontacting said inner conducting member.

16. An electron discharge device having a header member including acollar having a radially directed flange and an insulating memberextending across and within said collar and sealed thereto on the innersurface only of said collar, a plurality of lead wires sealed throughsaid insulating member, a cathode supported solely on said lead wires, acup-shaped anode positioned over said cathode and a collar of insulatingmaterial sealed between said flange and the open end of said cup-shapedanode.

17. An electron discharge device having a header member including acollar having a radially directed flange .and an insulating memberextending across and within said collar and sealed thereto, a pluralityof lead wires sealed through said insulating member, a cathode supportedon said lead wires, an elongated tubular member having a lip sealed tosaid Ilange, a grid surrounding said cathode mounted on said elongatedtubular member, a cup-shaped anode positioned over said cathode and gridand a collar of insulating material sealed between said flange and theopen end of said cup-shaped anode.

18. An electron discharge device having a header member including a rstcollar having a radially directed flange and an insulating memberextending across .and within said first collar and sealed thereto, aplurality of lead wires symmetrically arranged and sealed through saidinsulating member, a cup-shaped cathode supported on said lead Wires, anelongated tubular member having a lip sealed to said ilange, a gridsurrounding said cathode and mounted on said tubular member, acup-shaped anode positioned over vsaid anode and grid and having acollar of U-shaped transverse section at its open end, the inner lipbeing sealed to said anode, a second collar having `a iiange sealed tothe flange of the first collar, and a collar of insulating materialsealed between the outer lip of said U-shaped collar and the secondcollar.

19. An electron discharge device having a header member including acollar having a radially directed flange and an insulating memberextending across and within said collar and sealed thereto, a pluralityof lead Wires sealed through said insulating member, a cathode supportedon said lead wires, an elongated tubular member having a lip sealed tosaid flange, 4a grid surrounding said cathode and mounted on saidtubular member, a cup-shaped anode positioned over said anode and gridand a collar of insulating material sealed between said ilange and theopen end of said cup-shaped anode, said cathode and grid comprisingcup-shaped members, said grid including a, cap having an aperturetherein and means extending from the cathode through said aperturepositioning said cathode relative to said grid, said means beinginsulated from said cap.

LEON S. NERGAARD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,404,363 Chevigny July 23, 19462,283,895 Mouromtsei et al. May 19, 1942 2,353,743 McArthur July 18,1944 2,367,332 Bondley Jan. 16, 1945 Disclaimer 2,431,273.Leon S.Nergaard, Princeton, N. J. ELmemRoN DISCHARGE DEVICE EMPLOYING A CAVITYRESONATOR. Patent dated Nov. 18, 1947. Dsclaimer filed Aug. 5, 1949, bythe assignee Radio Corporation of America. Hereby enters this disclaimerto claims 3, 6, 7, 9, 10, 11, and 14 of said patent.

[Qicial Gazette Sept. 13, 1.949.]

